


An Unexpected Harmony

by Gathering_Stars



Category: Undertale (Video Game), 四月は君の嘘 | Shigatsu wa Kimi no Uso | Your lie in April
Genre: AU is also called ClassicTale, Celloes, Classical Music, Contests, DEAL WITH IT, Depression, F/F, F/M, Feels, Female Reader, Frisk did a genocide run before doing the pacifist, Humans and monsters live peacefully, I changed the archive warning now, I swear, More Crying, More tags will be added later, Not Anymore, Papy the Piper, Pianoes, Post-Pacifist, Post-Pacifist Route, Reader Is Not Frisk, Reader can play the violin, Sans the skeleton on a piano, Self made AU, Shigatsu wa Kimi no Uso/Your Lie in April, Sickness, Someone dies, Third Person POV, Undertale AU, Undyne the cello player, Violins, alphys and reader are friends, anime talk, as in rlly rlly sad, be prepared, but happiness doesn't last long, but oh well, crossovers ayeee, crying rivers lmao, feels overload, happy endings don't exist here, i didn't want to spoil you guys, i'm not joking on this, it's called InstrumentTale, kaori and reader are friends, my undertale game logic sucks, no terrorist groups, nope - Freeform, prepare a box of tissues bc this one is going to get sad, prepare to cry, prepare to cry even more, sans thinks that reader likes kousei, storyline is based off the anime itself, too late, undertale - Freeform, we'll find out if he's wrong or right, yay
Language: English
Status: In-Progress
Published: 2016-04-06
Updated: 2016-04-15
Packaged: 2018-05-31 16:29:17
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 3
Words: 3,249
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6477589
Author URL: https://archiveofourown.org/users/Gathering_Stars/pseuds/Gathering_Stars
Summary: <blockquote class="userstuff">
              <p>Sans cannot play the piano with emotion. He's slowly being swallowed up by the depression he's had ever since Frisk fell into the underground, ever since they tried the Genocide Run. He's always seen the world in monotone, free of all colour, lacking of emotions. But when he meets a violinist with a loud personality, his life decides to take a turn... For the better, and once more for the worse.</p>
            </blockquote>





	1. A Strong Melody

**Author's Note:**

  * For [requiescence](https://archiveofourown.org/users/requiescence/gifts).



> This story is set in an AU I made, called InstrumentTale or ClassicTale. In this AU, the main monsters (Toriel, Asgore, Alphys, Undyne, Papyrus, Sans, Flowey/Asriel) can play a certain instrument, mostly on the classical strings side, such as pianos, violins, cellos, etc. It is also set in this environment where the humans and monsters actually live in peace. Post-Pacifist.

 

Notes.

The sound of notes are all that fill the hall, the notes being created by a woman, with the use of a beautifully crafted violin.  
A skeleton watches her from his seat in this large hall, the tunes playing from her violin familiar. He recognizes the piece that she's playing. It's Violin Sonata No. 9 from the Kreutzer set piece, all pieces belonging to Beethoven, First Movement. It's a beautiful tune that starts out calm, and then intensifies.

He was never really interested in the violin-- the piano was his forte.

Sans, yes, that was his name, was only here to watch with his friend Alphys.

Alphys enjoyed violin music greatly, and wanted to learn how to play the instrument herself. She was introduced to classical music first by her girlfriend, Undyne, who plays the cello. Alphys was introduced to the violin by her other friend, _____, who was actually the current performer in the competition.

Alphys originally wanted Undyne to accompany her to the event, but since Undyne had to practice for her upcoming competition, Alphys asked Sans to accompany her in Undyne's place. Besides the fact that Sans and Alphys are good friends, Alphys had the thought of introducing Sans to her friend, _____.

Sans agreed to accompany Alphys, just to listen to the music.

 

  
_____ was playing with all her strength, her emotions pouring out through her playing.

Alphys knew this was her signature style of playing, but for Sans, who was watching her play for the first time ever, this was surprising to him. He never saw anyone play with such emotion like ______ did. He was only used to playing by the score, making sure to show no emotions as he played. He lived his life in monotone-- depression slowly pulling him deeper into the water, threatening to choke him to death. His depression came from the countless Genocide Runs Frisk had done before doing the Pacifist Route. Even though it was all over, Sans was scared that they would reset, and that everything he had would be taken away from him once more. That was why his depression wouldn't leave him. His depression always loomed in the back of his mind, and whenever he felt the happiest, his depression would suddenly put a knife to his neck and bring him to sadness. He hid his depression, however. He channeled it through his playing. No one noticed that way. He thought that it was better that way.

Sometimes, he refused to play at all, finding no reason to.

He could sense from the way she played that she was confident. Confident and strong-willed.

She finished playing the piece with a flourish, leaving the audience in awe.

As she bowed, many people in the audience stood up and clapped for her.

A standing ovation.

To Sans, it was quite obvious that this woman was very skilled at the art of playing the violin. One would easily think like that because of how the audience clapped for her.

Her playing was _definitely_ something.


	2. That Kind of Performance

**Summary for the Chapter:**

> After the performance, Sans meets the woman who has amazingly enchanting playing. He tells her what kind of performance he thinks it is.
> 
> And when she tells her best friend, Kaori, about what Sans said, Kaori is shocked to find out.

**Notes for the Chapter:**

> Kaori is mentioned in this chapter. This isn't entirely following the canon of the anime. More like an in-between-the-scenes thing. I'm sorry, I really love the anime and it's plot, but for the sake of this story, I can't follow the original plot of the anime entirely. Yes, there will still be the parts from the episodes, but mostly focusing on reader's side of the story. It's a crazy thing, sort of connected to the plot, but not the plot itself. Idk. I'm just rambling. Oh well.

After the competition, Alphys and Sans waited for _____.

As soon as she spotted them through the crowd of people, she started to make her way towards them, a cheerful bounce present in her every step, her hair bouncing slong with her movements.

Before she reaches them, however, two children timidly call her name, and hand her a bouquet of flowers.

She smiles at them, hugs them, and thanks them for the lovely flowers.

The flowers are a lovely shade of golden yellow, a shade Sans knows all too well.

 

* * *

 

  
______ finally reaches both Sans and Alphys, greeting them cheerfully before pulling Alphys into a hug.

"Alphys! Thanks for coming to my performance! How did I play?" She asks Alphys cheerfully.

"Y-you did g-great, _____!" Alphys replies.

"O-oh, and I w-want you t-to meet m-my friend here." Alphys added quickly, gesturing to Sans.

______ looked at him for a minute, and she spoke up.

"Hi there! It's nice to meet you...." She trailed off.

Sans suddenly realized that it's because she did not know his name, so he quickly filled in the blank.

"sans. sans the skeleton. i'd say it's a pleasure to meet you too, ______. a ton of people enjoyed your performance. a skele-ton. heh."

Despite his depression, Sans still told puns and jokes. It was another way of his that he used to hide his depression festering deep within him. It really helped him conceal the depression, besides pulling off his lack of will to live as laziness at its best.

_______ noticed that he just told a pun, and she laughed.

Her laugh was dainty and light, like the tinkling of bells. Soft, and like music to his ears. He thought she had a wonderful laugh, and made a note in his head to try to make her laugh like that again.

"Well, it's nice to meet you Sans! I see you like making puns." She says.

"heh, yeah. i just have an affinity for them. what can i say, though. after all, i am the bone-a-fide pun master." Sans replies, taking the chance to slip in another pun.

This makes her laugh again, and he finds himself smiling because of that.

He's not sure why.

"So, how was my performance?" She asks him, eyes lighting up.

If Sans was to be completely honest, words could not describe the performance she has given. But since he has to use words, he'll go with what he really thinks the performance is like, silently hoping that she would understand.

"there are these two girls who give you a bouquet of flowers. you don't know them, and they don't know you, and they probably bought the flowers at the last moment, just to give them to you. just for you. i think it was that kind of performance." Sans says.

She blinks at him. Once. Twice. Thrice.

And then she just hugs him, says her goodbyes to Alphys and him, and rushes off into the crowd of people.

Sans is astonished.

But even though he is surprised, even though her actions shocked him to the point he can't speak, he still finds himself thinking about her, and when he might be able to see her smiling face again.

 

* * *

 

_____walked up to Kaori, her violin in it's case, her carrying it on her back, and a bouquet of golden yellow flowers in her hands.

"Kaori-chan! How was my performance?" The girl asked her best friend.

"It was great, _____-chan!" Kaori replied cheerfully.

"Although, it would have been nicer if you played my piece instead." Kaori added with a friendly wink.

_____ swatted her friend's shoulder playfully.

"If only I had the time to learn it!" She replied, smiling.

"Next time, I'll be sure to teach you." Kaori said.

_____ smiled wider, and then suddenly remembered someone.

"Kaori-chan... If you have the time, I'd like to introduce you to my friend, Alphys." ____ told Kaori.

"That would be nice, _____-chan. Who is Alphys?" Kaori asked ____.

"Alphys used to be the Royal Scientist of the monsters! We met at this bookstore, when she asked me for a manga reccomendation. She's very nice once you get to know her, although, she is a little shy and stutters a lot." _____ replied.

"Hmm... I've never actually talked to any of the monsters before... I usually talk to you or to Kousei, sometimes to Tsubaki. It would be really nice to finally be friends with one!" Kaori said.

"I actually talked to her earlier, before going to you. She let me meet one of her friends. His name is Sans, and he's a skeleton. If I befriend him like I befriended Alphys, perhaps I can also introduce him to you, Kaori-chan!" ____ said.

"That would be nice! Does he play any instrument?" Kaori asks.

"I've yet to ask him, Kaori-chan. But it seems to me that he enjoys classical music very much." ______ replied.

"What made you think that, _____-chan? Did he say anything about your performance?" Kaori asked.

"Well.... He did say a few things about my performance that really flattered me.... Even though I don't think my performance went _that_ well..." _____ replied, suddenly finding the floor to be very interesting.

"I think you've taken quite an interest to him, ____-chan! You're blushing!" Kaori says teasingly.

"No, I'm not blushing!" _____ denies, even though her cheeks are turning a slight red.

"Okay, okay. I won't bother you about it anymore." Kaori says, secretly noting her friend's denial in her head.

"What did he say about your performance, ____-chan?" Kaori asks.

"Well... There were these two little girls who gave me a bouquet of yellow flowers, and I guess he saw them give it to me, so he said..."

"'There are these two girls who give you a bouquet of flowers. You don't know them, and they don't know you, and they probably bought the flowers at the last moment, just to give them to you. Just for you. I think it was that kind of performance.'" _____ says.

Kaori just stares at her friend, processing what she just said.

Kaori thinks it's familiar, and then suddenly, she remembers.

It's similar to what Kousei said about _her_ performance of the Kreutzer.

"_____-chan..." Kaori calls her friend's name quietly.

"Yes, Kaori-chan?" ____ answers.

"This may seem strange, but promise me you won't freak out." Kaori says.

"I promise I won't freak out." _____ promises.

"Okay..." Kaori takes a deep breath.

"What that Sans person said is similar to what Kousei said about my performance of the Kreutzer." Kaori says quietly.

____ just stares at her in disbelief.

**Notes for the Chapter:**

> Aaaaaaaand there you have it! I worked pretty hard on this one, but it still sucks, so eh, what does it matter. I know, I know, it doesn't make much sense, but ehhhhh this is what my brain told me to write, so what can I do?
> 
> Sorry that my chapters are really short...
> 
> Scream at me if you want an explanation.


	3. My World in Colour

**Summary for the Chapter:**

> A little get-together at Toriel's house leaves ____ with new friendships, and leaves Sans deeper in love with her than he was before.

**Notes for the Chapter:**

> Okay, so here's another chapter.
> 
> Sorry if these are really short!
> 
> Also, please excuse my horrible plot. I'm writing at 4:35 am.
> 
> Well, I hope you enjoy.

Sans still can't stop thinking about her.

Her smile, the way her eyes light up when she talks to Alphys, the way she plays the violin, even just the simple bounce in her step as the walks

He remembered something Alphys had told him once

_'The moment I met her, my life changed. Everything I saw, everything I heard, everything I felt... All the scenery around me started to take on colour.'_

_'That's when I knew that I had fallen in love with her.'_

Sans thought about what Alphys had told him, and about _____.

"hmm... maybe i'm just fooling myself..." Sans mused quietly to himself.

But then he thought about how when he saw her, he could see every streak of sunlight that shined on her face in a beautiful shade of yellow. He could see the golden yellow brilliance of the bouqet of flowers in her hands. He could see the amazing sparkles in her eyes. He saw those sparkles in Undyne's eyes and in Alphys' eyes as well.

And then he remembered how he wanted to see her smile again, how he wanted to hear her laugh again. He remembered the strange urge he got to protect her from every foe and save her from every battle. He remembered that strange feeling he got, the one that made him want to stay with her and make her happy for as long as he could.

Okay, so maybe he was in love with her.   
He wondered how one could fall in love with someone they just met.   
Maybe love at first sight exists? He doesn't know-- he never bothered with love until he met _____.

He looked outside, and once more thought of her, and then ne realized that he could see the blue that painted the sky. It was nice, he thought, to see it again.

"so, i guess what alph told me was true after all." Sans said quietly to himself as he sat down in the chair in front of the piano sitting in the house he and his brother Papyrus lived in.

"when you're in love with somebody, everything looks colourful."

 

* * *

 

 

_____ took a deep breath.

She looked at herself in the mirror, making sure that she looked decent.

She _should_ look decent. After all, she was visiting the former Queen of the Monsters. Who wouldn't look decent in the company of royalty, even if that royalty had already stepped down from the throne?

After changing her earrings to something that matched what she wore, she took one last look in the mirror. Pleased with her look, she picked up her bag, exited the house, and then locked the door behind her.

She checked her phone for the address that Alphys had given her, and once she had a good idea of where it would be, she started walking, enjoying the scenery around her.

 

* * *

 

_____ knocked on the door of a beautiful house.

A monster opened the door, a tall monster that looked very much like a white goat.

_____ recocgnized the monster as the former Queen of the Monsters, Toriel.

"Hello! Come inside, dear, and make yourself at home."

The former Queen of the Monsters ushered _____ inside her home, treating her with the same kindness she showed to Frisk when Frisk fell into the Underground.

_____ was shocked that the former Queen of the Monsters just called her 'dear', but she just decided not to think about it too much.

When she took a few more steps, she found herself in what looked like the living room, or family room-- as some might put it, of the house.   
It was a cozy area, a light brown couch/sofa sitting in front of a television, an ecru-coloured loveseat to the left of the couch/sofa and a dark blue bean bag with purple polka-dots on the right.

Her friend, Alphys, was sitting on the loveseat next to her girlfriend, Undyne. Sans was sitting in the middle of the couch, his younger brother, Papyrus (Alphys had told ______ about him), sitting on his right. The Ambassador of the Monsters, Frisk, was sitting contentedly on the bean bag, a small smile on their innocent face.

Alphys waved at _____, and gestured to the space beside Sans.

____ took her seat, and started talking to Alphys, their conversation about the latest episodes of the anime "Mew Mew Kissy Cutie" and the latest manga releases of the anime/manga series "Hetalia", particularly "Hetalia: World ☆ Stars".

____ didn't notice Ex-Queen Toriel slip quietly into the kitchen to bake some pie.

 

* * *

 

While _____ continued talking to Alphys, (this time, about a really good anime that they both just finished watching two nights ago while doing FaceTime with each other called "Shigatsu wa Kimi no Uso"/"Your Lie in April") the Ex-Queen slipped back into the living room, two plates with a slice of pie on each of them that emitted a delicious smelling aroma in her hands, the forks on the plates as well.

_____ arubtly cut off her conversation with Alphys, stood up, and bowed in the presence of Toriel, which surprised Sans to the point that he jumped a little in his seat.

"It is such a great honour to be in your presence, your former Majesty." _____ greeted, addressing Toriel.

Toriel seemed flattered and surprised at the same time, then chuckled a little, smiling warmly at _____.

"Thank you, dear, I am honoured to be in your presence as well. But I'll have you know that there is no need to be so formal with me-- I am an Ex-Queen, after all. Calling me 'Toriel' would be just fine." Toriel said.

"Are you sure?" ____ asked.

"Yes, dear, I am quite sure. I do not think I could still be called a Queen, and I will only choose to be one once the time of need arises. I really prefer that you would call me 'Toriel'." Toriel said surely.

"Okay, Toriel." ____ said, smiling at Toriel.

Toriel simply smiled back.

During this conversation _____ and Toriel had, Undyne had noticed the pies Toriel had been bringing, and had been quietly trying to take one of the plates until Toriel suddenly noticed her.

"Oh! Undyne, would you like a piece?" Toriel asked Undyne.

"HECK YEAH, I WOULD LOVE ONE!" Undyne said in pure joy, taking one of the plates and digging into the pie.

Toriel asked Alphys, and Alphys timidly took the other plate, thanking Toriel for her kindness.

Toriel looked over at _____ and told her that she had more pie in the kitchen.

Toriel hurried back to the kitchen to prepare some more slices of pie.

 

* * *

 

After everyone had already eaten their respective pieces of pie and all the plates were cleared and placed in the kitchen sink, various topics were brought up and words were exchanged between Toriel, Alphys, Undyne, Papyrus, Sans, Frisk (through writing words down on paper since _____ didn't fully understand sign language) and ______.

Toriel, Frisk, Undyne and Papyrus were introduced to _____, and _____ got to know each of them better, to the point of befriending them like she befriended Alphys. They also got to know ______ better, almost as close to her as Alphys is.

______ took a certain liking to Frisk, treating them like her own sibling.

______ also took this time to get to know Sans more, since not many words were exchanged when they first met. She had this strong feeling towards him, but she just decided to ignore it. It was probably just a crush, after all. Nothing but a crush.

 

* * *

 

Sans was enjoying every second he spent with her.

The smile she had on her face was contagious, and he found himself smiling as well.

He got to know her a little more, and soon befriended her.

He learnt that she liked reading books. He learnt that she loved watching sunsets and sunrises. He learnt that she loved stargazing on nights with full moons. He learnt that she loved early mornings. He learnt that she liked sweets. He learnt that she believed that every person had a purpose. He learnt that she believed that even the worst person can become better. He learnt that she loved snow. He learnt that she loved jokes. He learnt that she liked cherry blossoms. He learnt that she loved all the colours. He learnt that she loved jackets and hoodies. He learnt that she loved maple leaves during Autumn.

He learnt that he was falling in love with her even more.

 

* * *

 

Everyone had a really great time at Toriel's house.

The sunset was about to begin, and since everyone wanted to be home before dark, they all bid each other goodbye.

Alphys and Undyne had already left, and _____ was about to leave as well when suddenly Sans called her.

"hey ____. do you mind if we swap phone numbers?" He asked, holding out his phone to her.

She smiled, and replied.

"That would be great, Sans! I would love to swap phone numbers with you!"

"awesome." Sans replied, and then handed her his phone.

She handed Sans her phone, and they typed their respective phone numbers on the phones.

When _____ got her phone back, she hugged Sans.

Sans was completely thrown off guard.

He hesitated a little before hugging her back.

"Thanks Sans. It was great spending time with you and the others." _____ said.

"thank you, too. i had an amazing time as well. and _tibia_ honest, i would love it if we did something like this again." Sans replied.

_____ laughed, then released him from her hug.

She bid him goodbye, she bid Papyrus goodbye, she also bid Toriel and Frisk goodbye after thanking Toriel.

She then left.

Sans watched her with a newfound sparkle in his eyes.

He was in love.

**Notes for the Chapter:**

> Forgive me and my cheesy cliche thing.
> 
> Forgive me.
> 
> Scream at me if you need further explanation.

**Author's Note:**

> Since I assigned the main monsters to instruments, here they are.
> 
> Sans plays the piano.  
> Undyne plays the cello.  
> Papyrus plays the flute.  
> Alphys plays the recorder flute, but wishes to play the violin.  
> Toriel has yet to be assigned an instrument.  
> Asgore can play the acoustic guitar.  
> Flowey/Asriel can play the pan.
> 
> If you have any suggestions of instruments for the other monsters, and for Toriel and Frisk, I would love to hear them!
> 
> Feedback is greatly appreciated.
> 
> I try to update as much as I can.


End file.
